Bleaching method and composition



Patented Apr. 15, 1930 UNITED STATES PATENT OFFICE WILLIAM B. STODDARD,OF STAMFORD, CONNECTICUT, ASSIGNOR TO PILOT LABORA- TORY, INC., OFARLINGTON, NEW JERSEY, A CORPORATION 01 NEW JERSEY nmmcnmo mmnon ANDcomrosrrron W No Drawing.

My invention relates to an organic peroxide and per-acid composition andto its method of manufacture, and to a method of bleaching organicmaterials with organic peroxides and similar compounds.

Organic peroxides are, in general, unstable compounds subject todecomposition and oxidation with evolution of heat and are, therefore,of an explosive nature. Consequently their production, transportationand use in a pure form are hazardous, inasmuch as an initial, localdecomposition, induced by the hydrolytic action of moisture orotherwise, tends to increase with progressive speed and violence. Toreduce this hazard the peroxides, which are generally in the form of afine powder, are mixed with powdered, inert materials such as dicalciumphosphate which, by absorption of heat, prevent the local accelerationof the decomposition and the resulting tendency to explode. To becompletely effective, the inert material must be very intimately andfinely mixed with the peroxide to produce an entirely homogeneousmixture in order to ensure against local concentrations or masses'of thepure peroxide. A perfectly uniform mechanical mixture of two powders,such as the inert material and the peroxide is, however, not obtainedeasily and with certainty.

To remove to the greatest possible extent all tendency to hydrolyticdecomposition the peroxides must, at the time of their manufacture, becarefully and completely dried by means of a current of heated air. Thisdrying, however, adds to the complexity and the hazards of manufacture,as heating and drying in this manner may itself induce suchdecomposition.

When the peroxides are used in the bleaching of milling products such asflour, the necessity of mixing a small amount of the peroxide inpowdered form uniformly and finely throughout the flour also limits theeffectiveness of the peroxide, in that, at best only a limited surfacecontact between the particles of flour and the particles of peroxide isobtained. Moreover, as the coloring matter to be oxidized is largelyenclosed or dissolved in the fatty or waxy constituents Applicationfiled October 28, 1928. Serial No. 814,545.

of the flour and is thus not directly accessible to the peroxide, whichdirectly touches only a the surface of the .waxy particles,

the oxidizing and bleaching action of the of bleaching materials withorganic peroxides or per-acids in which the peroxides and materials arebrought into the most efi'ective relation for efiicient action; toprovide a simple and non-hazardous method of making dry peroxides orper-acids; to provide a peroxide composition in which homogeneity anduniformity may be ensured; and to a method of bleaching in which theorganic peroxide or per-acid may be applied homogeneously andwithuniformity to various types of material to be treated.

With these and other objects in view, which will more fully appearhereinafter, the invention comprises the peroxide composition and itsmethod of manufacture and the method of bleaching organic materials bymeans of the peroxide compositions described and set forth in thefollowing specification and claims.

In my invention the organic peroxide or per-acid or a mixture of organicperoxides or per-acids is dissolved in an organic solvent such as aninert mineral oil, a vegetable or animal oil, hydrocarbons of thealiphatic or of the aromatic series, acetone, ethyl acetate, orothersuitable non-aqueous solvents. By dissolving the peroxides insolvents of this character, a uniform, homogeneous composition isobtained. Contrary to what might be expected when inflammable organicoils that, under normal conditions, are inert to the peroxide, are mixedwith the peroxide, the peroxide is thereby stabilized and renderedsecure against violent decomposition and explosion. Inasmuch as theperoxides are in solution in the solvent, the composition is uniformthroughout and the existence of local masses of the peroxide, in whichthe decomposition once initiated would proceed with increasing force, isavoided. Any heat generated by the decomposition of the dissolvedperoxide is immediately quenched in the body of the solvent.

Although the dissolved peroxides are stabilized against violentdecomposition, their bleaching activity is increased. This may be due,in large part, to a greater uniformity in their distribution throughoutthe material to be bleached for, instead of being disseminatedthroughout the material in discrete particles, the solvent tends to wetand seep or creep uniformly throughout each particle, thereby bringingan equal amount of the peroxide to each portion to be bleached.-Moreover, where the chromophoric materials of the substance to bebleached are dissolved or contained within waxy or oily constituents, asis usually the case in milling products, and a mutual solvent of thesewaxy constituents and the peroxide is employed in which to dissolve theperoxides, the two may be brought into a common solution and thus intothe most effective relation for reaction.

Any suitable peroxy compound such as organic peroxides or per-acids maybe used. As examples, peroxides or peroxy compounds of the higher fattyacids such as caproyl, lauryl, palmityl, oleyl, stearyl peroxides andper-acids or mixtures thereof, or mixed per- A oxides of these acids andothers may be used.

These peroxides and peroxy compounds of the higher fatty acids are, ingeneral, soluble to a greater or. less extent in mineral oils and othernon-aqueous solvents.

In producing the peroxide composition of my invention, the method ofobtaining a dry peroxide is greatly simplified. To obtain a dry,non-aqueous solution of the peroxide, the peroxide may be simplydissolved in the nonaqueous solvent and the solution then driedchemically by means of a suitable drying agent, such for example asanhydrous calcium chloride, sodium sulphate, etc., thereby elimi-,nating the necessity for drying with air at elevated temperatures withthe attendant danger of local overheating and of initiating an 1explosive reaction.

In bleaching materials with the peroxy composition of my presentinvention, the material may be sprayed into a stream of flour or othermilling product, or into a stream of any desired material to bebleached. An initial fine and uniform distribution of the compositionthroughout the material to@ be bleached is thus obtained and issupplemented by a further spreading of the disseminated particlesthroughout the composition.

As an example of the manner of forming and stabilizing organic peroxidecom ounds according to my invention, the followmg detailed process isgiven: In a vessel fitted with an agitator are placed litres of hydrogenperoxide solution of a strength of 7 of hydrogen peroxide. To this thereare then added about 150 litres of a 1% sea solution. The resultingsolution is then cooled by the addition of chipped ice an the mixture isagitated. During the agitation, 22 litres of a caustic soda solutioncontaining 0.35 kgs. of commercial caustic soda per litre, and 30 kgs.of a mixture of acid chlorides containing 25 kgs. of cocoanut oil acidchlorides, and 5 kgs. of benzoyl' chloride, are

t oroutghly added simultaneously. .The reaction mixture is kept near 00., throughout the operation by the continued addition of chipped .ice.After the completion of the reaction, which may take from 10 to 20minutes, and which may be detected by the disappearance of the odor ofacid chloride, the mixture may be employed is a chemically inert,tasteless andodorless, petroleum distillate of low volatility which isknown in the trade as Marcel. The quantity of the solvent, Marcol isthen added directly to the bath and, after all of the peroxide isdissolved and taken up therein, the solvent and the dissolved peroxideare permitted to rise to the top, and the watery portion is drawn offfrom below the oily layer. The slightly moist, oily layer of peroxidesolution is then washed with water and is thoroughly and com letelydried by the addition of particles 0 anhydrous calcium chloride orsodium sulphate, which are thereafter filtered from the peroxidesolution.

The dry peroxide solution resulting from the above steps is found to bea relatively suitable and eflicient bleaching agent as comsolutionproduced. In using the composition for bleaching materials such asflour, it will be brought to a fine state of sub-division and suspensionin the atmosphere by spraying.

If used for bleaching liquid oils, the peroxy solution may be mixeddirectly with-the oil and a solvent that is, itself, miscible or solublein the oil being treated is selected.

As changes of o eration could be made within the scope o my invention,it is intended that all matter contained in the above description orshown in the accompanying drawings shall be interpreted as illustrativeand not in a limiting sense. 0

Having now described my invention what I claim as new and desire tosecure by Letters Patent is:

1. A composition of the type described which comprises an organicperoxid dissolved in a non-aqueous solvent.

2. A composition of the type described which comprises a non-aqueoussolution of a peroxy compound of a fatty acid.

3. A composition of the type described which comprises a non-a ueoussolution of a complex peroxid of a atty acid and an aromatic acid.

4. A composition of the type described which comprises an inert mineraloil solvent and a complex peroxid of a fatty acid and.

of benzoic acid dissolved in said mineral oil solvent. I a

5. A method of bleaching which comprises treating the material to bebleached with a non aqueous solution of an organic peroxy compound.

6. A method of bleaching which comprises dissolving an organic peroxycompound in a non-aqueous solvent and disseminating said solutionthroughout the material to be bleached.

7. A method of bleaching which comprises dissolving an organic peroxycompound in a solvent of the chromophoric constituents of said materialto be bleached, and mixing said solution with said material to bebleached.

8. A method of bleaching which comprises acting upon the chromophoricconstituents of the material to be bleaclied with organic peroxycompounds in a common solution with said chromophoric constituents.

9. A method of forming peroxy compounds which comprises treating an acylchloride with hydrogen peroxide to form an organic peroxide, dissolvingsaid peroxide in a nonaqueous solvent, and chemically drying theresulting peroxide SOllltlOEl.

10. A method of forming a peroxy composition which comprises treating amixture of a fatt acid chloride and benzoyl chloride with hy rogeneroxide to form a compound organic peroxi e, dissolving said peroxide ina non-aqueous solvent, and chemically drying said peroxide solution. A

11. A method of forming peroxy compositions which comprises treating anacyl chloride with hydrogen peroxide, dissolving the resulting organicperoxide in a nonaqueous solvent, and drying. the resulting solutionwith an anhydrous salt.

12. A method of bleaching flour and other milling products whichcomprises spraying a non-a ueous solution of organic peroxides Y uniformy throughout said milling products,

and permitting said peroxides to react therewith,

13. A method of bleaching flour and other milling products whichcomprises spraying a non-aqueous solution of eroxy compounds of organicacids throug out said milling products, said non-aqueous solvent being asolvent for the waxy chromophoric constituents of said milling product,and permitting said sprayed solution to remain in contact with andspread throughout said milling products.

14. A composition of the type described which comprises an inert mineraloil solvent and a mixture of complex peroxides of cocoanut oil fattyacid derivatives and of henzoic acid dissolved in said mineral oilsolvent.

15. A method of forming a peroxy composition which comprises treating amixture of cocoanut oil fatty acid chlorides and benzoyl chloride withhydrogen peroxide to form a mixture of complex organic peroxides,dissolving said peroxides in -a non-a ueous solvent, and chemicallydrying sai peroxide solution.

16. A method of forming a peroxy composition which comprises treating amixture of cocoanut oil fatty acid chlorides and benzoyl chloride inapproximately molecular proportions with hydrogen peroxide to form amixture of complex organic peroxides, dissolving said peroxide in anon-aqueous solvent, and chemically drying said peroxide solution.

17. A method of bleaching flour and other milling products whichcomprises s raying a non-aqueous solution of a mixture 0 peroxycompounds, benzoic acid and cocoanut oil fatty acid derivativesthroughout said milling products, said non-aqueous solvent being asolvent for the waxy chromophoric constituents of said milling products,and permitting said sprayed solution to remain in contact with and tospread throughout said milling products.

In testimony whereof I hereunto afiix my signature.

WILLIAM B. STQDDARD.

